@ EVargas nice of you taking your time to investigate :)

Yup Tried every variable every time a full new setup, even changing the Primitives used, went through the whole 3D Texture Line, with each the same issues also used all sorts of lights including Environment lightning . If it is a Driver issue, well that could be a problem finding the NVidia version that is working :( At least it still works in the older P13 versions, but hoping for a solution .... 

The Issue was mentioned already back in October and the solution was to use the new PrincipledVolume, well this does for sure not replace the ability of 3D textures :)

https://www.renderosity.com/forums/threads/2981929/slowdown-in-poser-131449-in-some-cases

So I do not seem to be the only one experiencing the Issue.